Debris flow disasters are one of the main types of geological disasters experienced worldwide, especially in China. With the economic development of mountainous areas and the development of western China, the demands on debris flow project management are becoming increasingly vigorous. Drainage channels, as one of the main types of debris flow prevention and control projects, are widely applied in debris flow hazard mitigation.
Following the Wenchuan Earthquake, massive collapses and landslides have provided rich solid material sources for the formation of debris flows and a large number of debris flows have been triggered in gullies with steep gully bed slopes of greater than 0.20 and even up to 0.50-0.60. For a debris flow with a large or steep gully bed slope, if the debris flow is discharged using a commonly used fully lined debris flow drainage channel (commonly known as a V-type drainage channel), a situation occurs in which the debris flow intensely abrades the channel bottom because the debris flow velocity in the channel is too high. This greatly reduces the service life of the drainage channel, and the maintenance cost of the operating period is increased. For a debris flow with a steep gully bed slope, if the debris flow is discharged using a ground-sill soft-foundation energy-dissipating debris flow drainage channel (commonly known as a Dongchuan-type drainage channel), when the distance between ground sills is large, a situation occurs in which, because the decrease in altitude of the debris flow is excessive, the debris flow scours the channel bottom by intensely acting on the soil body of the channel bottom. This threatens the safety of the ground sills, thereby resulting in the destruction of the drainage channel. When the distance between ground sills is small, the project investment will be greatly increased, and the safety of the ground sills cannot be ensured. For a debris flow gully with steep slopes, if the debris flows are discharged using a cage-lined debris flow drainage channel (ZL201110380681.5), the prevention and control effect on the low-frequency debris flows are good. However, for high-frequency debris flows, because the abrasion resistance and impact resistance of the wall of the energy dissipation structure are limited, a situation easily occurs in which the wall of the energy dissipation structure is damaged, and thus, the control effect on the debris flows is greatly reduced.